Helical earth



United States Patent [72] lnventors Hikoitsu Watanabe No S-l3, l-chome, Ehara-cho, Nakanoku, Tokyo; Sanji Genma, No. 4-8, l-chome, Egaracho, Nakano-ku, Tokyo, Japan [56] References Cited I UNITED STATES PATENTS 693 ,55 S 2/1902 Lclong 174/6X 1,244,118 10/1917 Mullen l74/6X Primary Examiner-Laramie E. Askin Attorney-Jocies and Greenside ABSTRACT: A suitable length of an electrically conductive metallic strip, bar or wire is wound into a helical earth having an engaging member formed at the lower end thereof for engagement with a driving rod for driving said earth into the ground. The driving force is applied to the upper end of the driving rod so as to drive into the ground the driving rod together with the earth and after having driven into a predetermined depth of setting, the driving rod is pulled out.

while the earth is set positively in place in the ground. Fabrication of the earth and the setting thereof are much facilitated and the better contact of the earth with the surrounding soil can be ensured.

PATENTED nun 5 I970 SHEET 1 BF 3 m TOR. Hikoitsu Watanabe and Sa Conma BY WM Their Attorneys PATENTED DEE} 519m SHEET .2 OF 3 FIG.7'

1 FIGJO 48 INVENTOR.

and Sanj i Gcnma Hikoitsu watanabe V Their Attorneys PATENTED DEC] 51970 SHEET 3 BF 3 F1613 FIG.I2 FIG/4 t INVENTOR. Hikoicsu watanabe and Sanji Ccnma HELICAL EARTH BACKGROUND OFTI-IE INVENTION The present invention relates to an earth for safeguarding an electrical apparatus and equipment and for preventing electrolytic corrosion of underground steel pipes or the like.

Generally it is preferable to set the earth to a depth at which the soil conditions such as moisture thereof can be maintained constant without being influenced by the dry or wet condition of the surface soil.

Widely used is an electrically earthing or grounding method in which a plurality of earth rods in the form of a bar or pipe made of an electrically conductive metal are driven underground one by one and connected with one with another so that the whole earth rod assembly may reach a considerably deep depth of setting.

However, socket joints are required forjoining the earth rods and the diameter of the socket joint is inevitably larger than the outer diameter of earth rod so that when the earth rod is driven underground the socket joint enlarges the earth hole larger than the earth rod. Therefore, the earth rod is driven into the hole whose diameter is larger than that of the earth rod so that the earth rod cannot closely contact with the surrounding soil, resulting in poor or ineffective electrical earthing or grounding.

In order to eliminate such a defect as described above, there has been proposed a method in which earth pipes are connected with each other by means of nipples and earth rods are joined by screw threads or by other suitable joint means so that the diameter of the joint between the pipes or rods never exceeds that of the pipe or rod. In this method, the earth can be set in better electrically contact relation with the surrounding soil, but in case of such physical connection or joint including the first mentioned socket joint, the joints are susceptible to corrosion when the earth has been set underground for a long time so that the electrical connection in the joint is reduced. In the worst case, the joints are completely electrically separated so that the earth cannot serve its object any longer. Furthermore the fabrication cost. becomes expensive because the joint portions must be machined and the earth must have large dimensions because it is driven underground to a considerable depth.

Furthermore, widely used is a method in -which after the earth having been driven underground, an electrically conductive solution is poured into or around the earth so as to form a better electrically conductive soil layer around the earth thereby reducing electrical resistance between the earth and its surrounding soil.

In this method, pipes having a plurality of holes perforated therein are used and after the pipe has been driven underground, the electrically conductive solution is poured from the upper open end of the pipe so that the solution may filtrate through the holes into the surrounding soiLthereby forming an electrically conductive layer around the pipe. In this case, the fabrication cost becomes more expensive because the holes must be formed. Such an earthing pipe therefore does not meet the demands for more readily applicable and less inexpensive earthing or ground means for various electrical apparatus.

SUMMARY OF THE INVENTION The primary object of the present invention is therefore to provide a novel earth which can completely eliminate the above-described defects encountered in the conventional earth. The present invention is characterized in that a length of an electrically conductive strip, baror wire is wound in a form of a helix having a uniform diameter or in a form of a flat spiral, the lower end of said earth having an engaging member which is adapted to engage with the leading end of a driving rod for driving underground the earth;'and after theearth has been driven underground together with the driving rod, only the latter is pulled out from the ground so that the earth may be retained to set to a predetermined depth of setting. Because of the construction of the earth of the present invention, the driving operation and the fabrication of the earth is much facilitated. Furthermore, the pitches of the helically wound earth may serve as spaces for passing water therethrough so that an electrically conductive solution poured into the earth from the upper open end thereof may filtrate into the soil surrounding the earth, thereby forming an electrically conductive soil layer therearound.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings in which:

FIG. 1 is a front view of one embodiment of a helical earth according to the present invention;

FIG. 2 is a top view thereof;

FIG. 3 is a front view of one modification of the helical earth of FIG. 1;

FIG. 4 is a top view thereof; v

FIG. 5 is another embodiment of the present invention in which the earth is wound into flat spiral form instead of being wound into a helical shape as shown in FIG. 1;

FIG. 6 is a top view thereof;

FIG. 7 is a front view of still another embodiment of the present invention similar in the form to that of FIG. 5;

FIG. 8 is a top view thereof;

FIG. 9 is a side view of one embodiment of a driving rod;

FIG. 10 is a side view of another embodiment of a driving rod; and 4 FIGS. 11 to 14 are side views for explanation of the earth driving. 7

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS In FIG. 1 is shown an earth 20 of the present invention comprising a main body 22 consisting of a helically wound elongated plate or strip, a lead wire 24 attached to the uppermost end of the main body 22 and an engaging portion 26 formed at the lowermost portion thereof.

The helically wound main body 22 is made of an elongated plate or strip having suitable length and width and a good electrical conductivity. The strip is wound in the helical form having the same outer diameter throughout the whole length thereof with a suitable pitch for providing spaces 28 between the adjacent turns which serve as waterdraining grooves. At the upper end of the helically wound main body 22 is fixed the lead wire 24 by for example brazing in order to flow the current to the main body 22. The lower end of the main body 22 is bent radially inwardly as best shown in FIG. 2, thereby forming the engaging portion 26 which has a pawl element 30 securely fixed thereto.

In case of the embodiment shown in FIGS. 3 and 4, instead of the strip, a wire is used for forming thehelical main body 22a of the earth 20a. The wire is wound up helically and the lower end thereof is slightly radially inwardly bent and has the engaging member 26a in the form of a cylinder fixed thereto by for example brazing. Other constructions are similar to those of the embodiment shown in FIGS. 1 and 2 in that the pitches or spaces 28a are formed between the adjacent turns so as to serve as a water draining groove and thelead wire 24a is fixed to the upper end of the helical main body 22a by for example brazing.

The third embodiment of the present invention shown in FIGS. 5 and 6 is similar in construction and material to the earth shown in FIGS. 1 and 2. That is, the main body 22b is made of an electrically conductive metallic strip having suitable length and width, but in the third embodiment the strip is wound up in the flat spiral form. Therefore, when the inner and outer ends of this main body 22b are vertically pulled in the opposite directions the main body 22b is then extended into the helical form as in the case of the embodiment shown in FIGS. 1 and 2.

[At the outer end of the main body 22b which becomes the upper end when extended is fixed the lead wire 24b by brazing or the like. The inner end which becomes the lower end when eittended is inwardly radially bent so as to form the engaging member 26b having the pawl element 30b attached thereto.

"A fourth embodiment of the present invention shown in FIGS. 7 and 8 is similar to that shown in FIGS. and 6 with the exception that the main body 22c of this earth 20c consists of a spirally wound wire made of a good electrically conductive metal and at the inner end thereof which becomes the lower end when extended is attached the cylindrical engaging member 260 by brazing or the like. As in the case of the third embodiment shown in FIGS. 5 and 6, the lead wire 24c is attached to the outer end of the main body which becomes the upper end thereof when extended, by brazing or the like.

: ,FIGS. 9 and 10 illustrate thedriving rods respectively for driving into the ground the earths to 200 having the constructions as described with reference to-FIGS. l to 8. The

'driving rod 40 shown in FIG. 9 is especially adapted to drive the earths 20 and 20b shown in FIGS. 1 and 2; and 5 and 6 into the ground. For this purpose,- the driving rod 40 comprises a rod portion 42 whose diameter is slightly smaller than the outer diameters of the earths 20 and 20b, a head 44 formed at the upper end of the rod portion 42 and a conical driving shoe 46 formed at'the lower end of the rod portion 42. The conical driving shoe 46 is provided with a groove 48 into which is fitted the engaging portions or members 26 or 26b of the earth 20 or 20b.

fThe driving rod 50 shown in FIG. 10 is adapted to drive into the ground the earths 20a and 20c shown in FIGS. 3 and 4; 7 and 8 respectively, and comprises rod portion 52 having an outer diameter slightly smaller than those of the earths 20a and 200, a head 54 formed at the top of the rod portion 52, a reduced diameter portion 58 which is adapted to fit into the cylindrical engaging member 26a or 26c of the earth 20a or 20c and a conical and sharp-pointed driving shoe 56 formed at the leading end of the reduced diameter portion 58.

- of setting of the earth, the rod portion 42 or 52 may consist of for example three rods 42a, 42b and 42c or 52a, 52b and 520. In this case, the lowermost rod 42a or 52a is provided with the above-described conical driving shoe 46 having the groove 48 formed therein or with the reduced portion 58 having the driving shoe 56 formed at the lower end thereof,. Preferably, these individual rods 42;, 42b and 420 or 52a, 52b and 520 are detachably connected with one another in unitary construction by means of screw threads 60 or 62. It is also preferable that the head 44 or 54 may be selectively and detachably connected to one of the upper ends of the rods 42a, 42b and 42c of 52a, 52b and 52c by screw threads 60 or 62.

When the driving rod 40 or 50 consisting of a plurality of rod portions as described above is used for driving the earth into the ground, the head 44 or 54 is screwed into the screw threads 60 or 62 at the upper end portion of the lowermost rod portion 42a or 52a and then the driving rod is driven into the ground. Before the head 44 or 54 is driven into the ground, the head 44 or 54 is removed from the rod portion 424 or 52 a and tlien the second rod portion 42b or 52b is connected by screws 60 or 62 to the upper end of the first or lowermost rod portion 420 or 52a while the head 44 or 54 is attached to the upper endof the second rod portion 42b or 52b. Thereafter, the driving rod is driven again into the ground. In the similar manner, thelength of the driving rod 40 or 50 may be extended to a desired length.

Therefore, when the earth 20 shown in FIGS. 1 and 2 or the earth 20b shown in FIGS. 5 and 6 is driven underground the driving rod 40 is first fitted into the earth and the groove 48 at the leading end thereof is fitted with the engaging portion 26 or 26b of the earth 20 or 20b. In this state, the driving rod 40 is driven into the ground when the impact is applied to the head 44 ,s'othat the earth 20 or 201) is also driven into the ground. In this case, the helically wound earth 20 having the same diameter throughout its length is driven into the ground as the driving rod 40 is driven into the ground, but the spirally-wound earth 20b is unwound from its inner end toward the outer end as the driving rod 40 is driven into the ground because the unwound earth 20b is wound around the driving rod 40 and extended therewith, thus forming the pitches or spacings 28b which serve as water passages. It should be noted that in this case the extendable driving rod 40 of the type described hereinabove may be of course utilized, by connecting the rod portions 42a, 42b, 42c and so on.

When the earth is driven into the ground to a desired depth of setting as shown in FIGS. 11 and 12, the driving rod 40 may be pulled out by applying the pulling force to the head thereof so that the groove 48 of the driving rod 40 is released from the engaging member 26 or 26b of the earth 20 or 20b while the earth 20 or 20b is set in place at a desired depth, maintaining a desired helical form. It will be seen therefore that the outer peripheral portions of the earth can positively contact with the surrounding soil, thus providing the complete earthing or grounding. Therefore when an electrically conductive solution which serves to reduce electrical resistance between the earth and its surrounding soil is poured from the upper open end of the earth 20 or 2%, the solution penetrates through the spacings 28 or 28b into the surrounding soil, thereby forming perfect electrically conductive layer around the earth.

In case of driving the earth 20a and 20c shown in FIGS. 3 and 4; and 7 and 8 respectively, the driving rod 50 shown in FIG. 10 is used. The driving rod 50 is fitted into the earth 20a or 20c so that the reduced diameter portion 58'of the driving rod may fit into the engaging'member 26a or 26c of the earth 20a or 200. Thereafter, the driving force is applied to the head so that the upper end portion of the engaging member 26a or 26c of the earth 20a or 200 receives theimpact force from the shoulder portion 64 between the rod portion 52 and the reduced diameter portion 58, whereby the earth 20a is driven into the ground. In case of the earth 200, the spirally wound earth is unwound from its inner end and wound around the driving rod 50 so that the earth is driven into the ground while forming suitable spacings 28c which serve as water passages. When the earth is set as shown in FIGS. 13 or 14, the force is applied to the head of the driving rod 50 so as to pull it out of the soil. Then, the earth 20a or 200 is set in a desired depth of setting while retaining its helical form with complete contact with the surrounding soil. Thereafter, an electrically conductive solution which serves to reduce electrical resistance between the earth and its surrounding soil is poured from the upper open end of the earth. The solution penetrates through the spacings 28a and 280 into the surrounding soil, thereby forming an electrically conductive soil layer therearound.

The present invention has been so far described with particular reference to some preferred embodiments thereof, but it will be understood that variations and modifications can be effected without departing from the true spirit of the present invention as described hereinabove and as defined in the appended claims.

We claim:

1. An earth comprising a main body consisting of a length of an electrically conductive metallic element having suitable length and cross section and being wound in a helical form having a uniform outer diameter throughout the whole length thereof, a lead wire attached to the top of said main body, and an engaging member formed at the lower end of said main body by inwardly radially bending the lower end portion of said main body and having a pawl element attached thereto.

2. An earth comprising a main body consisting of a length of an electrically conductive metallic element having suitable length and cross section and being wound in a helical form an electrically conductive metallic element having suitable length and cross section and being wound in a flat spiral form, a lead wire attached to the outer end of said main body which becomes the upper end of said earth when said spirally wound main body is extended, and an engaging member in the form of a cylinder attached to the inner end of said main body which becomes the lower end of said earth when extended. 

